These games are played only because of that, and they do just fine, if not better than the million of shooter clones being spewed out of EA and Activision.
And what do you call a game? The millions of hipster indies out there?
"Games teach" is about the simplest definition I can give.
Basically, human psychology means that we're obsessed with patterns. Humans learn patterns because they want to do the least work possible, and its easier to learn a pattern and then reuse that stored answer instead of having to constantly relearn it every time. This is what studying in school is.
Games are a series of patterns that the player has to learn in order to overcome some challenge. The problem with most games, especially the ones you pointed out, are that they have predictable patterns. Once you learn the pattern, you're never really challenged by it again (except by physical skill, but that's different).
Portal is a good example. The puzzles are pretty unique, fun and interesting and require you to learn through your own experimentation, which makes it more likely for you to retain the information. The only problem is that each puzzle/challenge/pattern will usually have one answer. There are some puzzles with multiple solutions, but Portal is not itself dynamic, which means that players will eventually master the game's puzzles, get bored and move on.
A true game is able to generate its own puzzles with no one answer, so that the user/player can discover it, and is able to teach through player action and thought, not just through railroading them with tutorials and popups.
